30 August 2010

Migraine linked to mortality risk

MORE evidence linking migraine with aura to an increase in the risk of cardiovascular and all-cause mortality has been reported in two articles published in the BMJ.

In a 26-year follow-up study of over 18 000 middle-aged men and women, Icelandic researchers found that, for people who had migraine with aura (compared with people with no headache), the relative risk of dying from all causes increased by 21%, and from cardiovascular disease by 27%. The risk was not increased for those with migraine without aura.(1)

While the 10-year absolute risk was considered low (0.6% in women and 1.2% in men), the authors recommended cardiovascular risk factor modification be a high priority among patients with the disorder.

A second migraine study, involving 27 860 women older than 45 years, found the risk of haemorrhagic stroke more than doubled among women who had migraine with aura compared with women with no history of migraine.(2)

However, the authors cautioned against definitive conclusions about the association in view of the low number of haemorrhagic strokes (85 overall, with only nine among women with migraine with aura) and the relatively low attributable risk.

The two studies add weight to findings from numerous studies conducted in recent years that indicate that migraine with aura is a risk factor for cardiovascular disease.

Commenting on both studies, Professor Graeme Hankey, head of the Stroke Unit at Royal Perth Hospital, said a patient’s risk assessment should be based on their age, sex, blood pressure, cholesterol, blood sugar, smoking status, family history and history of migraine with aura.

If their risk was more than 15% in the next 5 years, or 3% per year, they should aim to lower their risk by stopping smoking and reducing blood pressure and cholesterol, and antiplatelet therapy should be considered, he said.

“I think all patients should be properly informed of their risks, and by this I mean not just relative risks but more importantly absolute risks, with appropriate qualifiers or caveats that the risk assessment is based on epidemiological studies which may not be valid and generalisable to the individuals.”

Professor Hankey said people with migraine with aura constituted about one-fifth to one-third of migraineurs.

An editorial accompanying the articles said future research was needed to assess whether prophylaxis for migraine reduced cardiovascular and cerebrovascular events.(3)